In recent years, there has been a massive growth in the use of PCDs as such devices have become lighter, cheaper and with greater processing power and battery life. The functionality of such devices has also increased: mobile phones, for example, typically incorporate features beyond making telephone calls and sending SMS messages, such as music and video playback, games and interne browsing. Another typical feature of a PCD is that of a built-in camera. The use of such cameras has proved increasingly popular. However, due to the limited technical specifications of such cameras, they have tended to be used for simple snapshots only.